System for automatic feeding of furnaces with liquid fuel

ABSTRACT

A device for automatic feeding liquid fuel ( 2 ) to a furnace with comprising a power system for igniting, extinguishing, and monitoring the level of liquid fuel ( 2 ) in the furnace ( 1 ), said power system comprising a main power switch ( 9 ), a control circuit ( 3 ), a sensor of liquid fuel level ( 25 ), a fuel quality sensor ( 12 ), a first degree safety sensor ( 16 ), an additional safety sensor ( 15 ), a protective circuit ( 17 ), a supply circuit ( 18 ) and a spark generator ( 26 ); and said power system being remote-controlled; a fuel system for feeding liquid fuel ( 2 ) from a removable fuel tank ( 24 ) to the furnace ( 1 ) via a fuel pipe ( 13 ) and a solenoid valve ( 14 ); and an air system for generating of pressure to supply liquid fuel ( 2 ) to the furnace ( 1 ) comprising a power air pump ( 28 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C § 119 and the Paris Convention Treaty, this application claims the benefit of European Patent Application No. EP07460020 filed Aug. 22, 2007, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device for feeding liquid fuel to furnaces.

2. Description of the Related Art

Liquid fuel feeding systems for fireplaces are known and are described, for example, in Polish Pat. Appl. Nos. P-369839, P-375121, and P-376361. These feeding systems contain a power system, a fuel system, and an air system. The power system is remote-controlled and enables lighting and extinguishing of the fuel in the hearth, as well monitoring the level of fuel in the hearth. The fuel system feeds the hearth with liquid fuel from a detachable fuel tank via a solenoid valve in the fuel pipe. The air system is used to generate appropriate pressure in order to supply liquid fuel to the hearth. The power system also includes a safety sensor installed in the hearth, which is connected with a fuse of the power pump supplying liquid fuel to the hearth. However, these types of systems are not entirely safe and lack functionality. Accordingly, much opportunity for improvement remains.

SUMMARY OF THE INVENTION

The aim of this invention is to improve the system of automatic feeding of liquid fuel to furnaces known from prior art. The improved device shall increase the safety of use, render it impossible to use inappropriate liquid fuel, allow operation in case of voltage decay, and introduce the possibility of additional remote-control adjustment of the height of flame, as well as additional signalling of the system operating conditions.

The goal presented in the subject matter of the invention is accomplished by providing an improved device for automatic feeding of the hearth with liquid fuel in household heating appliances, especially fireplaces with or without chimney ducts, comprises a power system, a fuel system, and an air system, wherein a power control circuit was applied in the power system, and connected with a motion sensor and a fuel quality sensor installed in the fuel system in its fuel pipe before the solenoid valve, whereby the power system comprises an additional safety sensor installed in the hearth over the first degree safety sensor, which is connected only with the protective circuit inserted in the feeding circuit of the control circuit, whereby the protective circuit is connected with the main power switch.

An important feature of the feeding system solution is also the structure of the hearth, in which the combustion chamber is connected with the separated sensor chamber with an installed fuel level sensor, a first degree safety sensor and an additional safety sensor, whereby the fuel inlet is located in the sensor chamber, and from the top it is closed with a cover with ventilating holes, which also has a formed screen in the part adjoining the combustion chamber and slantwise shaped bottom, while the combustion chamber includes in its upper part a sliding screen operating in connection with a servo-mechanism, which allows smooth regulation of the flame.

The next important feature is constituted by the fact that in the power system the feeding circuit is also connected with the servo-mechanism for sliding of the hearth screen, with the motion sensor and micro-loudspeaker for acoustic signalling of the system operating conditions, as well as with a reset button for turning on after installing a new fuel holder, a button for turning the system into operation mode, and elements visually indicating the operating conditions, which are installed in the control panel located in the fireplace.

Moreover, the fact that in the power system the feeding circuit constitutes a system of buffer feeding, which is connected with the main power switch detachable low-voltage feeder and a battery in the circuit of which a blocking diode is installed, constitutes yet another important feature of this system.

As far as the method of operation is concerned, the functioning of the system of automatic hearth feeding with liquid fuel is characterized mainly by the fact that by means of the signal produced by the remote control or the button on the control panel the control circuit is actuated which starts the air pump generating excess pressure in the fuel holder, and opens the solenoid valve feeding the hearth with liquid fuel, whereby at the same time in the operating mode the fuel quality sensor that monitors the flowing fuel comes on, the fuel level sensors in the hearth and safety sensors also come on, and after the hearth is filled with liquid fuel, the spark-gap generator comes on automatically resulting in the flashover between permanent magnet machine electrodes, also the servomechanism of screen sliding in the hearth and the diodes indicating the working conditions of the system come on.

An important feature of the method of operation is also the fact that in the control circuit the stand-by mode turns on automatically, which without any interference from the user causes turning on of information functions related to the working condition of the feeding system.

A crucial feature of the method of operation of the system is the fact that in case of failure of the first degree protective sensor, an additional safety sensor shall be actuated, being continuously in the working mode, after turning on of the main feeding, resulting in autonomous isolation of the feeding circuit and therefore turning off the operating mode of the system. Permanent setting of the additional protection sensor in the operating mode, ever since turning on the main power switch, aims also at protection against attempts by the user to add liquid fuel manually to the hearth.

Favourable results that have been achieved in this new system of automatic feeding with liquid fuel are most of all obtaining full safety of the user and ensuring continuity of operation of the device fed with liquid fuel, together with visual and sound information on working conditions, as well as obtaining the possibility of smooth adjustment of the height of flame in the hearth.

The new system also eliminates emergencies that may occur when using fuel of inadequate quality, which is absolutely vital, for example, in fireplaces without chimney ducts.

Application of an additional sensor chamber in the hearth, where the fuel level sensor and two safety sensors as well as the liquid fuel inlet were installed, renders access to sensors impossible for unauthorized persons, also, the flame from the combustion chamber is not allowed in, which increases the reliability of sensors operation and extends their life time. The fuel inflow located in the sensor chamber in the direct proximity of sensors and its askew shaped bottom ensures also smaller inertia of their operation and decreases the hysteresis of fuel level in both the chambers, which in turn ensures quicker reaction of sensors.

The application of the internal battery power supply allows for uninterrupted operation of the device for a few days without necessity of connecting to any external current generator, while the battery charging system enables charging of the battery in the course of operation as well as when the system is turned off.

Also a very important advantageous feature of the system, as far as the safety of operation of the system is concerned, is the introduction of an additional protective system with an additional safety sensor located in the sensor chamber above the first degree safety sensor. This system, incorporated into the supply line, and connected neither with the control circuit nor with any other element of the feeding system, is free from possible influences on its operation by the said elements, and is reliable as it bases exclusively on the said additional sensor and a fusible cut-out.

A further advantageous feature of the system is the protection of the device against the situations of inadvertent stirring or attempts to move the device in the course of its operation. This is ensured by the motion sensor. The protection is also effective when using the device on the seismically active areas, in which case the sensor switches the system off when vibrations exceed the set amplitude, and thus preventing operation in hazardous conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinbelow with reference to accompanying drawings, in which:

FIG. 1 presents a schematic diagram of the automatic hearth feeding system in a household fireplace without a chimney duct;

FIG. 2 shows a sketch of the front view of a household fireplace with indication of the control panel installed on its front plate;

FIG. 3 shows a control panel,

FIG. 4 shows the perspective view of the hearth with visualization of the sliding screen cut out above the sensor chamber;

FIG. 5 shows a perspective view of the hearth without the screen with visualization of the cover of the sensor chamber; and

FIGS. 6-8 show in a diagrammatic and perspective view the 3 phases of the sliding screen over the hearth.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the automatic hearth feeding system 1 with liquid fuel 2 comprising the control circuit 3 actuated with the remote control 4 or the button 5 installed in the control panel 6 on the front plate 7 of the household fireplace 8 shown in FIGS. 2 and 3. Prior to turning on the control circuit 3, it is necessary to turn on the main power switch 9, which actuates the first indicating diode 10, which in turn informs that the system has been switched on and that it is ready to light up the fireplace 8. Turning on of the control circuit 3 and that the system is in operating mode are signalled by switching on of the second indicating diode 11 also installed on the control panel 6.

The system presented in FIG. 1 in its important features is characterized by the fact that the control circuit 3 is connected with the quality sensor 12 of liquid fuel 2 installed in the fuel pipe 13 before the inflow to the electro-valve 14. The quality sensor 12, made by Remtor, Poland, checks conductivity of liquid fuel 2. If the conductivity value of liquid fuel 2 has a predefined value, it is assumed that the fuel can be fed to the furnace or hearth 1 of the fireplace.

The electric system of the system comprises an additional safety sensor 15 installed in the hearth 1 above the first degree safety sensor 16, which is connected only with the protective circuit 17 incorporated into the supply circuit 18 of the control circuit 3, whereby the protective circuit 17 is connected with the main power switch 9. The control circuit 3 is also connected with the servo-mechanism 19 for the slide of the screen 20 of the hearth 1, with the motion sensor 21 and with the micro loud-speaker 22 for acoustic signalling the of the working conditions of the device, as well as with the reset button 23 for turning on after installation of a new fuel tank 24, and with the button 5 for switching the system into the operating mode, which are installed on the control panel 6 of the household fireplace 8.

The control circuit 3 is also electrically connected with the fuel level sensor 25, with spark-gap generator 26, which is further connected with the electrodes of the permanent magnet machine 27 installed in the hearth, and with an electric air pump 28, that via the air duct 29 supplies air to the fuel tank 24 in order to generate pressure inside, which results in the flow of liquid fuel 2 to the hearth 1. In the presented system, the supply circuit 18 constitutes the buffer feeding system, which is connected with the main power switch 9, with low-voltage feeder 30 and a battery 31, into the circuit of which a blocking diode 32 is also incorporated, which enables the passage of current only in one direction during the process of battery charging 31 from the supply circuit 18.

FIGS. 4 and 5 show the hearth 1 with the structure in which the combustion chamber 33 comprises, in the upper part, a sliding screen 20, functioning in connection with the servo-mechanism 19, which allows flame adjustment in a continuous manner. The combustion chamber 33 is connected with a separated sensor chamber 34, with the possibility of fuel flow, with the fuel level sensor 25 installed inside, with the first degree safety sensor 16, and an additional safety sensor 15, where the fuel inlet 35 is located in the sensor chamber 34, which is closed from the top with a cover 36 with ventilating holes 37, which also consists of a formed screen 38 in the part adjoining the combustion chamber 33 and an askew shaped bottom 341.

The automatic feeding system presented in FIG. 1 is, as far as the method of operating conditions are concerned, characterized by the fact that by the signal generated from the remote control 4 or the button 5, the control circuit 3 activates the power air pump 28 generating positive gauge pressure in the fuel tank 24 and opens the solenoid valve 14 feeding the hearth 1 with liquid fuel 2, whereby at the same time in the operating conditions the fuel quality sensor 12 turns on, which monitors the flowing liquid fuel 2 and then the following come on: fuel level sensor 25 in the hearth 1 and the first degree safety sensor 16, while the additional safety sensor 15 is turned on at the moment when the main power switch 9 is turned on. After filling in of the hearth 1 with liquid fuel 2, the spark-gap generator 26 turns on automatically resulting in the spark-over between the permanent magnet machine 27 electrodes, also switched on are the servo-mechanism 19 of the screen slide 20 in the hearth 1, diodes 10 and 11 signalling the operating mode of the system, as well as the acoustic signal.

Another important feature of the method of operation is the fact that in the control circuit 3 the stand-by mode turns on automatically during operation, which without interference from the user actuates the information functions on the conditions of the feeding system operation. An essential feature of the method of operation in the system is also the fact that in case of a break-down of the fuel level sensor 25 or the first degree protection sensor 16, an additional safety sensor 15 turns on, resulting in an automatic isolation of the supply circuit 18 and as a result of this—turning off of the operating mode of the system.

The functioning of the automatic hearth feeding system 1 with liquid fuel 2 enables the fuel in the fireplace 8 to burn, ensuring at the same time nearly 100% safety of use, maintaining constant level of fuel 2 in the hearth 1 in the course of operation. This function is accomplished thanks to the previously described system, where a control circuit 3 is used, and sensors connected with it: fuel quality sensor 12, first degree safety sensor 15, motion sensor 21 and fuel level sensor 25, as well as an additional protective circuit 17, connected with an additional safety sensor 15.

The system is additionally equipped with an internal power source—a battery 31, ensuring the possibility of continuous work for the period of several days and possibility of charging; the fireplace 8 may be operating in the course of the charging processes. The first indicating diode 10 lights up after the switching on the main power switch 9. It informs of the readiness of the system to operate (i.e., to fire up the fireplace 8).

The system may be turned on with the use of the remote control 4 or the button 5 installed on the control panel 6 of the fireplace 8. Turning on of the system is signalled by the lightning up of the second indicating diode 11. After turning on of the system, the control circuit 3 activates the power air pump 28 generating positive gauge pressure in the fuel tank 24, forcing the flow of fuel 2 via the fuel pipe 13 to the hearth 1, and, at the same time, the solenoid valve 14 is opened.

The fuel quality sensor 12, which continuously monitors the flowing liquid fuel 2 determining its suitability for use in the feeding system, is also turned into the operating mode. In case of detection of incorrect liquid fuel 2 or lack of fuel, the sensor sends this information to the control circuit 3, which activates an appropriate signal regarding diodes 10 and 11, informing the user on incorrect liquid fuel 2 or lack of fuel in the fuel tank 24. At the same time the servo-mechanism 19 is actuated sliding the screen 20 of the hearth 1 into the fully open position, as shown in FIG. 6.

In the course of filling the hearth 1 with liquid fuel 2, the fuel level sensor 25 located in the hearth 1 checks the level of fuel and sends appropriate information to the control circuit 3. Also the first degree safety sensor 15 sends an appropriate signal to the control circuit 3 in case of exceeding of the level of liquid fuel 2 in the hearth 1. The additional safety sensor 14 is permanently turned into the operating mode immediately after turning on of the system, and it is not connected with the control circuit 3, which ensures the highest level of operational reliability. This sensor shall be actuated only in a situation when the level of fuel 2 in the hearth 1 is exceeded above the allowed one and the first degree safety sensor 15 fails to correct it.

After the appropriate level of fuel 2 is reached in the hearth 1, the fuel level sensor 25 sends a signal to the control circuit 3, which turns off the subassemblies responsible for filling in the hearth 1. It closes the solenoid valve 14 and activates the sequence of generating spark from the spark generator 26 to permanent magnet machine's electrodes 27. This spark sparking over between the electrodes of the permanent magnet machine 27 on the level of the contact of fuel 1 with electrodes of the permanent magnet machine 27 and lights up the liquid fuel 2. After completion of the spark feeding sequence, the fireplace 8 works independently, and the control circuit 3 monitors in a continuous manner the level of fuel 2 in the hearth 1, regularly adding fuel so as to keep the adjusted level. After approximately 8 minutes from turning on the fireplace 8, the control circuit 3 activates the servo-mechanism 19 that closes the screen 20 of the hearth 1 to the initial position, as shown in FIG. 6.

Independent operation of the fireplace 8 continues up to the moment when it is turned off by the user or the liquid fuel 2 runs out in the fuel tank 24, or else until a situation which the system interprets as dangerous. If liquid fuel 2 runs out in the fuel tank 24, the fireplace 8 turns off and the lack of liquid fuel 2 shall be indicated by pulsation of one of the diodes, 10 or 11. In order to turn on the fireplace 8 again, a new fuel tank 24 has to be installed, and then the reset button 23 should be pressed, which shall result in the change of the diode's 10 lighting from pulsation into a constant lighting.

Turning off the fireplace 8 is possible by means the remote control 4 or the button 5. After turning off, the control circuit 3 switches off all the sub-assemblies and keeps the fireplace 1 open, to allow the remaining liquid fuel 2 to burn out. This is signalled by lighting of only a single diode 10. After approximately 8 minutes from turning off, the hearth 1 is completely closed with the screen 20, as shown in FIG. 8. (FIG. 7 shows sliding screen 20 in indirect position).

The feeding system of household heating devices to be used with a vent-free fireplace presented in the example incorporating important features of the invention does not exhaust all the possible variations of its embodiments.

This invention is not to be limited to the specific embodiments disclosed herein and modifications for various applications and other embodiments are intended to be included within the scope of the appended claims. While this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.

All publications and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application mentioned in this specification was specifically and individually indicated to be incorporated by reference. 

1. A device for automatic feeding of liquid fuel (2) to a furnace with comprising a power system for igniting, extinguishing, and monitoring the level of liquid fuel (2) in the furnace (1), said power system comprising a main power switch (9), a control circuit (3), a sensor of liquid fuel level (25), a fuel quality sensor (12), a first degree safety sensor (16), an additional safety sensor (15), a protective circuit (17), a supply circuit (18) and a spark generator (26); a fuel system for feeding liquid fuel (2) from a removable fuel tank (24) to the furnace (1) via a fuel pipe (13) and a solenoid valve (14); and an air system for generating of pressure to supply liquid fuel (2) to the furnace (1) comprising a power air pump (28); wherein said fuel quality sensor (12) is installed in said fuel pipe (13) of said fuel system upstream of said solenoid valve (14); said additional safety sensor (15) is installed in the furnace (1) above said first degree safety sensor (16) and is connected to said protective circuit (17); and said protective circuit (17) is connected to said main power switch (9).
 2. The device of claim 1, wherein the furnace (1) is a fireplace (8).
 3. The device of claim 1, wherein said power system is remote-controlled.
 4. The device of claim 1, wherein said furnace comprises a combustion chamber (33) connected to a separated sensor chamber (34); said fuel level sensor (25), said first degree safety sensor (16), said additional safety sensor (15), and a fuel inlet (35) are disposed in said separated sensor chamber (34); said separated sensor chamber (34) is closed from its top with a cover (36) having a plurality of ventilating holes (37) and a formed screen (38); and a sliding screen (20) for closing said combustion chamber (33) is engaged with a servo-mechanism (19).
 5. The device of claim 4, wherein said control circuit (3) comprises a motion sensor (21), a micro-loudspeaker (22), a reset button (23), and a power-on button (5), which are installed in a control panel (6), and said control circuit (3) is connected with said servo-mechanism (19).
 6. The device of claim 1, wherein said supply circuit (18) comprises a system of buffer feeding connected with the main power switch (9), a low-voltage feeder (30), a battery (31), and a blocking diode (32).
 7. A method for operating the device of claim 1, the method comprising generating a signal to switch on said control circuit (3), which in turn turns on said power air pump (28) for generating positive gauge pressure in the fuel tank (24) and opens said solenoid valve (14) feeding the furnace (1) with liquid fuel (2); and simultaneously turning on said fuel quality sensor (12) which monitors the flowing liquid fuel (2), and the fuel level sensors (25), and the safety sensors (15, 16); and upon filling of the furnace (1) with liquid fuel, (2), generating a spark in said spark generator (26).
 8. The method of claim 7 further comprising turning on indicating diodes (10, 11) to indicate to a user that the system in a working mode.
 9. The method of claim 7 further comprising the control circuit (3) automatically turning on during operation and processing information about conditions of the feeding system.
 10. The method of claim 7 further comprising in case of a failure of the first degree protection sensor (16), turning on said additional safety sensor (15).
 11. The method of claim 10 wherein turning on said additional safety sensor (15) results in an automatic isolation of the feeding circuit (18) and due to this turning off of the system operation mode. 